<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        /* .nav li 权重是0,0,1,1 */
        .nav li {
            color: red;
        }

        /* 把第一行的li改成粉色 加粗 */
        /* .nav .pink 权重是0,0,1,0 + 0,0,1,0 = 0,0,2,0 */
        .nav .pink {
            color: pink;
            font-weight: 700;
        }
    </style>
</head>

<body>
    <ul class="nav">
        <li class="pink">人生四大悲</li>
        <li>家里没宽带</li>
        <li>网速不够快</li>
        <li>手机没流量</li>
        <li>学校没wifi</li>
    </ul>
</body>

</html>